docs: def sql_key(self, generation, sql, params, order, result_type,
                  using='default'):
          """
          Return the specific cache key for the sql query described by the
          pieces of the query and the generation key.
          """
          # these keys will always look pretty opaque
          suffix = self.keygen.gen_key(sql, params, order, result_type)
          using = settings.DB_CACHE_KEYS[using]
          return '%s_%s_query_%s.%s' % (self.prefix, using, generation, suffix)